The present invention relates generally to radiation detectors and methods. More specifically, the present invention relates to high spatial resolution radiation detectors, assemblies and methods including methods of making the radiation detectors and using the detectors in performing radiation detection.
Scintillation spectrometers are widely used in detection and spectroscopy of energetic photons and/or particles (e.g., X-rays and gamma-rays). Such detectors are commonly used, for example, in nuclear and particle physics research, medical imaging, diffraction, non destructive testing, nuclear treaty verification and safeguards, nuclear non-proliferation monitoring, and geological exploration.
A wide variety of scintillators are now available and new scintillator compositions are being developed. Among currently available scintillators, thallium-doped alkali halide scintillators have proven useful and practical in a variety of applications. One example includes thallium doped cesium iodide (CsI(Tl)), which is a highly desired material for a wide variety of medical and industrial applications due to its excellent detection properties, low cost, and easy availability. Having a high conversion efficiency, a rapid initial decay, an emission in the visible range, and cubic structure that allows fabrication into microcolumnar films (see, e.g., U.S. Pat. No. 5,171,996), CsI(Tl) has found use in radiological imaging applications. Furthermore, its high density, high atomic number, and transparency to its own light make CsI(Tl) a material of choice for X-ray and gamma-ray spectroscopy, homeland security applications, and nuclear medicine applications such as intra-operative surgical probes and Single Photon Emission Computed Tomography or SPECT.
Scintillation spectrometry generally comprises a multi-step scheme. Specifically, scintillators work by converting energetic particles such as X-rays, gamma-rays, and the like, into a more easily detectable signal (e.g., visible light). Incident energetic photons are stopped by the scintillator material of the device and, as a result, the scintillator produces light photons mostly in the visible light range that can be detected, e.g., by a suitably placed photodetector. Various possible scintillator detector configurations are known. In general, scintillator based detectors typically include a scintillator material optically coupled to a photodetector. In many instances, scintillator material is incorporated into a radiation detection device by first depositing the scintillator material on a suitable substrate. A suitable substrate can include a photodetector or a portion thereof, or a separate scintillator panel is fabricated by depositing scintillator on a passive substrate, which is then incorporated into a detection device.
Improving performance of scintillator detectors is generally of great interest, for example, in order to make scintillation based detectors more useful and capable of filling existing and emerging technical needs. In imaging applications, for example, spatial resolution, or the minimum distance between distinguishable objects in an image, is one of the most important parameters. Recent advances in scintillator compositions and detector configurations, for example, have allowed improved spatial resolution, but further improvements are needed.
Thus, there is a need for improved techniques and methods, as well as devices and assemblies, for increasing performance parameters such as spatial resolution in scintillation based radiation detectors.